| Objective: To investigate the morphologic changes of aortic endothelial cells observed by atomic force microscopy (AFM) in diabetic rats and explore the effect of diabetes mellitus on the structure of the vascular endothelial cells. Methods: 36 SD rats were divided randomly into two groups: (1) the control group, 18 rats; (2) the diabetic group, 18 rats. The diabetic rat model was developed by intraperitoneal injection of streptozotocin. The rats were sacrificed and the thoracic aortas were drawn at the end of 2, 7 and 12 weeks. The morphologic changes of aortic endothelial cells were observed by AFM and the relative data were acquired with the IP software of the AFM.Results: (1) The changes of blood glucose: the blood glucose of the control group was between 5.75± 1.15~5.94 ±1.43 mmol/L and that of the diabetic group was between 27.28±2.29~32.88 ±2.76 mmol/L. The blood glucose of the diabetic group in 2, 7 and 12 weeks was significantly increased by comparison with that of the control group (P<0.05). (2) The qualitative results observed by AFM: the whole appearance of the vascular endothelia was constituted by a great deal of volcanic-crater-like ringed mountains and the arrangement of the endothelia orientated in the direction of the major axis of the blood vessel. Long shallow ditches orientated in the same direction could be observed obviously. There was no obvious difference between the whole appearance of the diabetic groups and that of the control groups. The membrane structures of the endothelia of the control group in different stages were scanned respectively by 50um, 20μm and 5μm scanner of AFM, and the results showed they did not change obviously. The cell nuclei were protuberant to the luminal surface and there were valley-like pits around the area of the cell nuclei. These pits were constituted by lots of cavernae that linked up together. On the surface of the endothelia there were many flaky, finger-like processes and numerous microvilli that orientated mostly in the same direction. The regular big and round window-hollow-like structures could also be observed and their inner structures were like labyrinthic channels. On the flatter area were lots of insect-bitten-like caveloae.At the end of 2 weeks the surface structures of the endothelia of the diabetic rats were more disorder than those of the control groups and the processes and microvilli were not so regular. With the advance of diabetes mellitus the surface structures of the endothelia were more and more disorder. The boundary of the window-hollow-like structures were irregular, just became as if they were weathered rocks. Especially in 12 weeks of diabetic rats, the ball-like, a-string-of-beads-like, coral-like and cauliflower-like granules adhering to vessels scattered on the endothelia and the number of them were increased significantly. These granules usually located at the boundary of the window-like structures. (3) The quantitative results observed by AFM: the change of Roughness of peak and valley (Rp-v) of diabetic group was similar to that of control group and in both groups in different stage Rp-v were gradually increased, but no significances. Rp-v of the diabetic group were significantly increased by comparison with that of the control group in the same stage (P<0.05). Roughness of root-means-square (Rrms) of the control group in each stage and Rrms of the diabetic group at 2 weeks and 7 weeks increased gradually, but no significances. Rrms of diabetic group in 12 weeks was significantly increased compared with that in 2, 7 weeks and that of the control group in 12 weeks (P<0.05). As the change of Rrms, Roughness of average (Ra) of the control group in different stage and Ra of the diabetic group in 2 and 7 weeks were not significantly increased, and Ra of diabetic group in 12 weeks were significantly increased compared with that in 2 and 7 weeks (P<0.05). Ra of the diabetic group in 7 and 12 weeks were significantly increased compared with that of the control group (P<0.05). There were no significances in Mean Height (Mean Ht)... |
